Explanation:
Icy world Charon is 1,200 kilometers across.
That makes Pluto's largest moon only about 1/10th the
size of planet Earth but a whopping 1/2 the diameter of
Pluto
itself.
Charon is seen in unprecedented
detail in this image from
New Horizons.
The image was captured late July 13
during
the spacecraft's flight through the Plutonian system
from a range of less than 500,000 kilometers.
For reference, the distance separating Earth and Moon is less than
400,000 kilometers.
Charonian terrain,
described as
surprising,
youthful, and varied, includes
a 1,000 kilometer swath of cliffs and troughs stretching below center,
a 7 to 9 kilometer deep canyon cutting the curve of the upper right edge,
and an enigmatic dark north polar region
unofficially
dubbed Mordor.